<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="js/vue.min.js"></script>
</head>
<body>
<div id="app">

    <h3>{{ age }}</h3>
    <input type="button" @click="add_age" value="点我">
    <input type="button" @click="change_age" value="点我">

</div>
<script>
    new Vue({
        el: "#app",
        data: {
            age: 19,
        },
        methods:{
            change_age(){
                this.age--;
            },
            add_age(){
                this.age++;
            }
        }

    })
</script>
</body>
</html>